Обсуждение: function to find difference between in days between two dates

Hello

PostgreSQL hasn't any official function for it. If you need it, you
can write own function

CREATE FUNCTION date_diff(date, date) returns integer as $$
select $1-$2; $$ language sql;

Regards
Pavel Stehule

2007/6/14, Ashish Karalkar <ashish.karalkar@info-spectrum.com>:
>
>
> Hello all,
>
> Is there any function to find  differences in days between two dates?
>
>
> I am using
>
> select abs(current_date - '2007-06-15')
>
> to get the desired result.
> but I think there must be a function and I am missing it,
> if so, can anybody please point me to that.
>
>
> Thanks in advance
>
> With regards
> Ashish Karalkar
>
>
>

On Thu, Jun 14, 2007 at 09:00:12AM +0200, Pavel Stehule wrote:
> Hello
>
> PostgreSQL hasn't any official function for it. If you need it, you
> can write own function

Not true. Anything that is done by an operator as actually done by a
function. So the function exists:

# \df date_mi
                       List of functions
   Schema   |  Name   | Result data type | Argument data types
------------+---------+------------------+---------------------
 pg_catalog | date_mi | integer          | date, date
(1 row)

You may have to dig through the pg_operator table to find it though.

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

2007/6/14, Martijn van Oosterhout <kleptog@svana.org>:
> On Thu, Jun 14, 2007 at 09:00:12AM +0200, Pavel Stehule wrote:
> > Hello
> >
> > PostgreSQL hasn't any official function for it. If you need it, you
> > can write own function
>
> Not true. Anything that is done by an operator as actually done by a
> function. So the function exists:
>
> # \df date_mi
>                        List of functions

I know about it, but it's undocumented

Pavel

On Thu, Jun 14, 2007 at 01:54:09PM +0200, Pavel Stehule wrote:
> ># \df date_mi
>
> I know about it, but it's undocumented

Hrm, yet Bruce mentions it in one of his documents.

http://momjian.us/main/writings/pgsql/data_processing.pdf

It may be undocumented, but it get a lot of hits on google :)

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

> Hrm, yet Bruce mentions it in one of his documents.
>
> http://momjian.us/main/writings/pgsql/data_processing.pdf
>
> It may be undocumented, but it get a lot of hits on google :)
>

why google? look to pgsql/src/backend/utils/adt/date.c  :-)

Regards
Pavel Stehule